Application of leakage current parameters for technical diagnostics of surge arresters

The work presents a method for the assessment of the technical condition of gapless surge arresters based on the analysis of the leakage current waveform and harmonic components distributions. In order to diagnose the arresters a measurement set was developed that can be used in a location where the arresters have been installed. The measurements are made by supplying the set from power network (on-line method) or from the external voltage source (off-line method). Based on the measurements of maximal, mean and harmonic components values of surge arrester leakage current, for the arresters from service, values of p
₁
and p
₂
coefficients are calculated, which are then related to the values of p
_1E
and p
_2E
coefficients determined for new arresters, included in the database. The introduction of p
₁
and p
₂
coefficients allows diagnosing different types of gapless surge arresters, irrespective of the voltage level of power network in which they were installed. The results of tests of selected surge arresters were presented - diagnosed with this method - which have been subject to different types of failure during operation.